Patent GB-845506-A (GB)
Title: Improvements in or relating to decoding equipment
Inventor: FRENCH JAMES ALFRED THOMAS
IPC: H04Q3/42
Filed: 1955-08-15
Abstract: 845,506. Automatic exchange systems. POSTMASTER GENERAL. Aug. 8, 1956 [Aug. 15, 1955], No. 23505/55. Classes 40 (4) and 40 (9). [Also in Group XXXVIII] Translating equipment comprises a plurality of input circuits each including a single input winding and each energizable independently of the others, a plurality of output leads each inductively coupled to a unique combination of input leads, some at least of the leads being inductively coupled to combinations of more than one input winding, an output appearing on an output lead only when the unique combination of input windings to which the lead is coupled is energized. Figs. 1a-1f show circuit elements used in the apparatus. In Fig. la pulses in a primary winding 2 induce pulses in a single turn code wire CW. A potential can be applied to terminal A to bias the rectifier MR to non-conducting condition to switch off the pulses. In Fig. lb the pulses are switched off when the core is saturated by current Ic. In Fig. 1c, depending on whether current is flowing through control winding 2 or not so the impedances of the mark windings 3 are low or high. Similarly in Fig. 1d the impedances of the windings 3 depend on whether or not a control potential is applied to terminal A. In Figs. le and 1f which are very similar to Figs. 1a and 1b the mark windings can be made to act as low-impedance pulse sources in which the pulses can be switched on or off under the control of potential on terminal A in the one case or current in wire Ic in the other case. Registration and translation of code digits. In Fig. 2 four code digits, named thousands, hundreds, tens, and units digits are used. Elements of the type described are arranged in two tree formations in respect of the units and tens, and thousands and hundreds digits, respectively, the code point A and B terminals being cross-connected by code wires which are threaded through selected translation rings. By lowering the impedance of appropriate thousands, hundreds, tens, and units windings a selected code wire, say 1211, is pulsed to induce a pulse in the secondary windings of the appropriate translation detector transformers and so operate trigger circuits. Various examples of possible arrangements are shown schematically in Figs. 3a-3e. In the preferred arrangement, Fig. 3e, wire AB conducts only when the pulses normally present on T1, T10, T100 are cut off so that pulse ES is able to pass through rectifier MR. Registration of code digits, Fig. 4. The code is stored by operation of relevant trigger circuits such as CS1/1. All the suppressor gates such as SG1/1, other than those inhibited by operated trigger circuits, are energized by a marking pulse PW1 which is also applied to all the code wire terminals C. A substantial pulse appears therefore only in the code wire corresponding to the code digits. This pulse may be used to set bi-stable trigger circuits, Fig. 4b, to produce continuous signal outputs or may be used to change the magnetic state of a core with a rectangular hysteresis loop, as shown in Fig. 4c. The apparatus shown in Fig. 4 may be used in marking circuits of the type described in Specifications 723,094 and 722,178 or it may be used as a register in computing-apparatus. Marker or translator, Fig. 5. Code digits are registered on triggers such as CS1. When translation is required a pulse is applied to trigger PT1 which applies a pulse of time "t 1 " to operate all the suppressor gates except those inhibited by the selected code triggers. The pulse after a delay "t 3 " is also applied by PT2 to code wire terminals C so that the selected code wire carries a substantial pulse. This code wire is threaded through selected translation detector rings to operate appropriate translation store triggers such as TS1. The translations may be changed rapidly by threading the wires AB through different combinations of translation rings.